Md. Raisuddin Khan

Walking Hexapod Robot in Disaster Recovery: Developing Algorithm for Terrain Negotiation and Navigation

The catastrophic cyclone Sidr that wrecked havoc Bangladesh in 2007, tsunami hit most of the countries of Asia around Indian ocean in 2004, Katrina hit Arkansas in 2005, and the terrorist attacks on the World Trade Centers in 2001 are clear indication that we are not prepared for disaster recovery at all. In all cases the infrastructure could not withstand the fury of nature, even in the case of WTC the NYPD was not prepared for such gigantic task of rescue mission. The conventional reaction to such disaster is not adequate; a new paradigm shift is needed to address such calamities utilizing all resources at hand. Disaster recovery is defined to be the emergency response function which deals with the collapse of man made structures (G. Nejat, 2006). In any disaster either man made or due to Mother nature, the elementary tasks at hand are: (i) reach the affected hazardous field (ii) find and get information about victims, and (iii) rescue as many of them as possible. It is possible for robot to reach any hazardous field unlike who have limited mobility in such missions. Nowadays legged and wheeled robots are involved in such mission (Habib, 2000), (Y. Mori, 2005), (Rizo J, 2003), (Y. Baudoin, 1999). In terms of hazardous field navigation for disaster recovery mission, legged robots have advantages over wheeled robots. Wheeled robots are the simplest and cheapest and tracked robots are very good for moving, but not over almost all kinds of terrain. Manned wheeled vehicles (Habib, 2000), (Y. Mori, 2005) or robotic systems (Rizo J, 2003), (Y. Baudoin, 1999), have already been tested. Navigate over obstacles and ditches and even on stairs one of the foremost advantages legged robots hold over their wheeled or tracked counterparts. It shows that legged robots can operate in both even and rough terrain. Some general-purpose robots were tested for this kind of application, nowadays specific prototypes having special features are being built and tested for specific mission. The TITAN VIII walking robot, a four-legged robot was developed as a general-purpose walking robot at the Tokyo Institute of Technology, Japan (Hirose S, 1998). COMET-I maybe the first legged robot purposefully developed for rescue missions. It is a six-legged robot developed at Chiba University, Japan, and incorporates different sensors and location systems (Nonami K, 2000), (Q.J. Huang, 2003). This robot weighs about 120 kg. The Chiba University group has developed the fourth version of this 22

Autonomous flexible snake robot for 3D motion

As a high redundancy system with high flexibility, disaster rescue robot is a demand for search and rescue inside collapsed buildings. A smart material actuated autonomous flexible snake robot is developed in this paper that is able to perform 3D (degree) motion. Real snake flexibility can be realized from 3D motion of the proposed flexible snake robot. The modelling of n-link snake robot is discussed first and then verified experimentally. Online gait generation is done using Central pattern generator (CPG) control system for autonomous navigation of the snake robot. The illustration of the robot modelling has been performed both theoretically and experimentally. The CPG-based online gait generation method allows continuous motion.

Electro-goniometric system: An instrumentation to capture knee movements for forward walking

Continuous monitoring, accuracy of evaluation, and proper analysis of human gait characteristics have presented the importance not only in clinical studies, but also in the field of sports, rehabilitation, training, and robotics research. Human knee joint plays an important role in balancing and stabilizing human body while walking. So it is obvious to observe knee joint movement characteristics as a part of gait analysis. In this paper, instrumentation for capturing knee joint movement pattern is presented. The instrumentation is designed based on Electro-goniometric mechanism with flexible joints on arms that attached with upper and lower extremity of lower limbs. The electrical signals obtained from the instrumentation are calibrated carefully to present the movement angles in degree. The instrumentation system is viable to represent knee movement pattern of human walking which is compared with the result of image based analysis.

Smart Tendon Actuated Flexible Actuator

We investigate the kinematic feasibility of a tendon-based flexible parallel platform actuator. Much of the research on tendon-driven Stewart platforms is devoted either to the completely restrained positioning mechanism (CRPM) or to one particular type of the incompletely restrained positioning mechanism (IRPM) where the external force is provided by the gravitational pull on the platform such as in cable-suspended Stewart platforms. An IRPM-based platform is proposed which uses the external force provided by a compliant member. The compliant central column allows the configuration to achieve DOFs with tendons. In particular, this investigation focuses on the angular deflection of the upper platform with respect to the lower platform. The application here is aimed at developing a linkable module that can be connected to one another so as to form a “snake robot” of sorts. Since locomotion takes precedence over positioning in this application, a 3-DOF Stewart platform is adopted. For an arbitrary angular displace of the end-effector, the corresponding length of each tendon can be determined through inverse kinematics. Mathematical singularities are investigated using the traditional analytical method of defining the Jacobian.

Analysis of engagement factor in trajectory tracking-based experiment

The main objective of this work is to study the degree of engagement levels of human subjects in completing a series of tasks based on their physiological signals. The tasks are in the form of tracking a set of trajectories on the computer screen by using a mouse... The subjects are chosen randomly based on both sexes, aged from 20 to 40 years old. After completing the required tasks in a series of experiments, the subjects are given a set of questions to answer In particular, for the experiment, the subjects are asked to track a set of prescribed paths within the allocated times in order to adhere to different speed constraints. Various shapes of trajectories with various colours are given to the subjects in order to study the degree of engagements while performing the tasks. In estimating the degree of engagement level, the physiological signals; namely the electrooculogram (EOG) are recorded by using the G-tec data acquisition system. By using these signals, information on the endogenous type of eye blinking is extracted. After completing the experiments, a set of questionnaires are given to the subjects to measure the degree of engagement level. The questionnaire works as an important tool to validate the engagement model deduced from the experiment done earlier by the subjects. Preliminary analysis on the questionnaire shows a good match to the deduction made from the experimental results.

A novel algorithm for collaborative behavior of multi-robot in autonomous reconnaissance

Robots in a group can solve problems in fundamentally different ways than individuals while achieving higher levels of performance, however, programming and coordination of a group of robots poses big challenge. This paper addresses the problem of mobile robots executing complex group behaviors in an attempt to form collaborative group behavior of hexapod robots in reconnaissance mission. A set of basic sharing behaviors for a group of hexapod robots is first assigned. These behaviors then evolve into more complicated group behaviors such as flocking using collaboration and indirect communication. This is then used to solve specific problems relating to goal finding and obstacle avoidance within a real world environment. The sharing behavior is designed with a stable navigation towards practical applications, such as reconnaissance mission and coordinated motion. All algorithms have been developed and tested on two hexapod robots.

A collaborative navigation algorithm for multi-agent robots in autonomous reconnaissance mission

Robots are playing an increasingly more important role as the technology is maturing. Robots are omnipresent; numerous robots committed to a single task will become ordinary. Multi-agent robots are capable of handling problems in many different ways than individuals while achieving higher levels of performance. But present unique challenges for developing collaborative navigation algorithm and coordination among themselves are not sufficient for autonomous collaborative tasks. Some research papers based on collaborative robots have been reviewed in this paper; from review analysis we have developed an algorithm with behavioral based distributed knowledge of multi-agents for accomplishing collaborative navigation. The goal of multi-agent robots is to move as a cohesive team by sharing their distributed learning behaviors and navigating in autonomous reconnaissance missions. Finally some preliminary experimental results will be presented of the developed collaborative navigation algorithm between robots to reach the target and achieve their goal sharing their knowledge.

Visual tracking and servoing of human face for robotic head Amir-II

In this paper, visual tracking and servoing of human face are implemented through image processing. A robotic humanoid head named Amir-II, equipped with web cam and servoing mechanism is used as the platform. The robotic head tracks the human face within the field-of-vision (FOV) while the servoing mechanism ensures the detected human face remains at the center of its FOV. The algorithm developed in this research utilizes the capability offered by scientific computing program MATLAB along with its Image Processing Toolbox. The algorithm basically compares the locations of the face in the image plane that is detected from the static face image captured from real-time video stream. The calculated difference is then used to produce appropriate motion command for the servo mechanism to keep track of the human face moving within the range of its FOV.

Gait analysis: systems, technologies, and importance

Human gait is the identity of a persons style and quality of life. Reliable cognition of gait properties over time, continuous monitoring, accuracy of evaluation, and proper analysis of human gait characteristics have demonstrated their importance not only in clinical and medical studies, but also in the field of sports, rehabilitation, training, and robotics research. Focusing on walking gait, this study presents an overview on gait mechanisms, common technologies used in gait analysis, and importance of this particular field of research. Firstly, available technologies that involved in gait analysis are briefly introduced in this paper by concentrating on the usability and limitations of the systems. Secondly, key gait parameters and motion characteristics are elucidated from four angles of views; one: gait phases and gait properties; two: center of mass and center of pressure (CoM-CoP) tracking profile; three: Ground Reaction Force (GRF) and impact, and four: muscle activation. Thirdly, the study focuses on the clinical observations of gait patterns in diagnosing gait abnormalities of impaired patients. The presentation also shows the importance of gait analysis in sports to improve performance as well as to avoid risk of injuries of sports personnel. Significance of gait analysis in robotic research is also illustrated in this part where the study focuses on robot assisted systems and its possible applicability in clinical rehabilitation and sports training.

Improvement of Dimensional Accuracy of 3-D Printed Parts using an Additive/Subtractive Based Hybrid Prototyping Approach

At present, two important processes, namely CNC machining and rapid prototyping (RP) are being used to create prototypes and functional products. Combining both additive and subtractive processes into a single platform would be advantageous. However, there are two important aspects need to be taken into consideration for this process hybridization. First is the integration of two different control systems for two processes and secondly maximizing workpiece alignment accuracy during the changeover step. Recently we have developed a new hybrid system which incorporates Fused Deposition Modelling (FDM) as RP Process and CNC grinding operation as subtractive manufacturing process into a single setup. Several objects were produced with different layer thickness for example 0.1 mm, 0.15 mm and 0.2 mm. It was observed that pure FDM method is unable to attain desired dimensional accuracy and can be improved by a considerable margin about 66% to 80%, if finishing operation by grinding is carried out. It was also observed layer thickness plays a role on the dimensional accuracy and best accuracy is achieved with the minimum layer thickness (0.1 mm).